Mechanism of pancreatic amylase will be probed by using chemically modified amylases as substrates, particularly those in which a very small fraction (e.g., 3%) of the OH groups has been replaced by H or F, or substrates in which double bonds have been introduced into a small proportion of the glucose residues. After amylase action on these modified substrates we will isolate the oligosaccharides containing the chemically altered glucose units, and analyze their structures. This will provide a record as to the exact position of the chemically altered group during the catalytic process. From this we can deduce the significance of each OH group in the substrate as regards its essentiality for substrate binding and catalysis. We are preparing lactones of higher oligosaccharides as putative transition state analogs. We will determine their inhibition characteristics to evaluate their structural similarity to the transition state. With beta amylase we will examine methanol as a possible covalent inhibitor (methyl ester of catalytic COOH group). The biochemical significance of the amylose-extender (ae) gene in corn starch biosynthesis will be examined by working out the structure of ae-wx amylopectin.